5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 1) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 2) * NBUS driver for TS-4600 based boards
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 3) *
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 4) * Copyright (c) 2016 - Savoir-faire Linux
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 5) * Author: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 6) *
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 7) * This file is licensed under the terms of the GNU General Public
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 8) * License version 2. This program is licensed "as is" without any
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 9) * warranty of any kind, whether express or implied.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 10) *
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 11) * This driver implements a GPIOs bit-banged bus, called the NBUS by Technologic
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 12) * Systems. It is used to communicate with the peripherals in the FPGA on the
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 13) * TS-4600 SoM.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 14) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 15)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 16) #include <linux/bitops.h>
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 17) #include <linux/gpio/consumer.h>
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 18) #include <linux/kernel.h>
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 19) #include <linux/module.h>
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 20) #include <linux/mutex.h>
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 21) #include <linux/of_platform.h>
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 22) #include <linux/platform_device.h>
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 23) #include <linux/pwm.h>
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 24) #include <linux/ts-nbus.h>
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 25)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 26) #define TS_NBUS_DIRECTION_IN 0
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 27) #define TS_NBUS_DIRECTION_OUT 1
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 28) #define TS_NBUS_WRITE_ADR 0
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 29) #define TS_NBUS_WRITE_VAL 1
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 30)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 31) struct ts_nbus {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 32) struct pwm_device *pwm;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 33) struct gpio_descs *data;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 34) struct gpio_desc *csn;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 35) struct gpio_desc *txrx;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 36) struct gpio_desc *strobe;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 37) struct gpio_desc *ale;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 38) struct gpio_desc *rdy;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 39) struct mutex lock;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 40) };
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 41)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 42) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 43) * request all gpios required by the bus.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 44) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 45) static int ts_nbus_init_pdata(struct platform_device *pdev, struct ts_nbus
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 46) *ts_nbus)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 47) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 48) ts_nbus->data = devm_gpiod_get_array(&pdev->dev, "ts,data",
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 49) GPIOD_OUT_HIGH);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 50) if (IS_ERR(ts_nbus->data)) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 51) dev_err(&pdev->dev, "failed to retrieve ts,data-gpio from dts\n");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 52) return PTR_ERR(ts_nbus->data);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 53) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 54)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 55) ts_nbus->csn = devm_gpiod_get(&pdev->dev, "ts,csn", GPIOD_OUT_HIGH);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 56) if (IS_ERR(ts_nbus->csn)) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 57) dev_err(&pdev->dev, "failed to retrieve ts,csn-gpio from dts\n");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 58) return PTR_ERR(ts_nbus->csn);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 59) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 60)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 61) ts_nbus->txrx = devm_gpiod_get(&pdev->dev, "ts,txrx", GPIOD_OUT_HIGH);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 62) if (IS_ERR(ts_nbus->txrx)) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 63) dev_err(&pdev->dev, "failed to retrieve ts,txrx-gpio from dts\n");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 64) return PTR_ERR(ts_nbus->txrx);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 65) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 66)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 67) ts_nbus->strobe = devm_gpiod_get(&pdev->dev, "ts,strobe", GPIOD_OUT_HIGH);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 68) if (IS_ERR(ts_nbus->strobe)) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 69) dev_err(&pdev->dev, "failed to retrieve ts,strobe-gpio from dts\n");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 70) return PTR_ERR(ts_nbus->strobe);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 71) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 72)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 73) ts_nbus->ale = devm_gpiod_get(&pdev->dev, "ts,ale", GPIOD_OUT_HIGH);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 74) if (IS_ERR(ts_nbus->ale)) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 75) dev_err(&pdev->dev, "failed to retrieve ts,ale-gpio from dts\n");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 76) return PTR_ERR(ts_nbus->ale);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 77) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 78)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 79) ts_nbus->rdy = devm_gpiod_get(&pdev->dev, "ts,rdy", GPIOD_IN);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 80) if (IS_ERR(ts_nbus->rdy)) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 81) dev_err(&pdev->dev, "failed to retrieve ts,rdy-gpio from dts\n");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 82) return PTR_ERR(ts_nbus->rdy);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 83) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 84)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 85) return 0;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 86) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 87)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 88) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 89) * the data gpios are used for reading and writing values, their directions
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 90) * should be adjusted accordingly.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 91) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 92) static void ts_nbus_set_direction(struct ts_nbus *ts_nbus, int direction)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 93) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 94) int i;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 95)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 96) for (i = 0; i < 8; i++) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 97) if (direction == TS_NBUS_DIRECTION_IN)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 98) gpiod_direction_input(ts_nbus->data->desc[i]);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 99) else
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 100) /* when used as output the default state of the data
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 101) * lines are set to high */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 102) gpiod_direction_output(ts_nbus->data->desc[i], 1);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 103) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 104) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 105)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 106) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 107) * reset the bus in its initial state.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 108) * The data, csn, strobe and ale lines must be zero'ed to let the FPGA knows a
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 109) * new transaction can be process.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 110) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 111) static void ts_nbus_reset_bus(struct ts_nbus *ts_nbus)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 112) {
b9762bebc6332 (Janusz Krzysztofik 2018-09-05 23:50:05 +0200 113) DECLARE_BITMAP(values, 8);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 114)
b9762bebc6332 (Janusz Krzysztofik 2018-09-05 23:50:05 +0200 115) values[0] = 0;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 116)
77588c14ac868 (Janusz Krzysztofik 2018-09-05 23:50:07 +0200 117) gpiod_set_array_value_cansleep(8, ts_nbus->data->desc,
77588c14ac868 (Janusz Krzysztofik 2018-09-05 23:50:07 +0200 118) ts_nbus->data->info, values);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 119) gpiod_set_value_cansleep(ts_nbus->csn, 0);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 120) gpiod_set_value_cansleep(ts_nbus->strobe, 0);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 121) gpiod_set_value_cansleep(ts_nbus->ale, 0);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 122) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 123)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 124) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 125) * let the FPGA knows it can process.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 126) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 127) static void ts_nbus_start_transaction(struct ts_nbus *ts_nbus)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 128) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 129) gpiod_set_value_cansleep(ts_nbus->strobe, 1);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 130) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 131)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 132) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 133) * read a byte value from the data gpios.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 134) * return 0 on success or negative errno on failure.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 135) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 136) static int ts_nbus_read_byte(struct ts_nbus *ts_nbus, u8 *val)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 137) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 138) struct gpio_descs *gpios = ts_nbus->data;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 139) int ret, i;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 140)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 141) *val = 0;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 142) for (i = 0; i < 8; i++) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 143) ret = gpiod_get_value_cansleep(gpios->desc[i]);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 144) if (ret < 0)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 145) return ret;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 146) if (ret)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 147) *val |= BIT(i);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 148) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 149)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 150) return 0;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 151) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 152)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 153) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 154) * set the data gpios accordingly to the byte value.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 155) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 156) static void ts_nbus_write_byte(struct ts_nbus *ts_nbus, u8 byte)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 157) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 158) struct gpio_descs *gpios = ts_nbus->data;
b9762bebc6332 (Janusz Krzysztofik 2018-09-05 23:50:05 +0200 159) DECLARE_BITMAP(values, 8);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 160)
b9762bebc6332 (Janusz Krzysztofik 2018-09-05 23:50:05 +0200 161) values[0] = byte;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 162)
77588c14ac868 (Janusz Krzysztofik 2018-09-05 23:50:07 +0200 163) gpiod_set_array_value_cansleep(8, gpios->desc, gpios->info, values);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 164) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 165)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 166) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 167) * reading the bus consists of resetting the bus, then notifying the FPGA to
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 168) * send the data in the data gpios and return the read value.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 169) * return 0 on success or negative errno on failure.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 170) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 171) static int ts_nbus_read_bus(struct ts_nbus *ts_nbus, u8 *val)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 172) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 173) ts_nbus_reset_bus(ts_nbus);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 174) ts_nbus_start_transaction(ts_nbus);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 175)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 176) return ts_nbus_read_byte(ts_nbus, val);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 177) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 178)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 179) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 180) * writing to the bus consists of resetting the bus, then define the type of
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 181) * command (address/value), write the data and notify the FPGA to retrieve the
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 182) * value in the data gpios.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 183) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 184) static void ts_nbus_write_bus(struct ts_nbus *ts_nbus, int cmd, u8 val)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 185) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 186) ts_nbus_reset_bus(ts_nbus);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 187)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 188) if (cmd == TS_NBUS_WRITE_ADR)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 189) gpiod_set_value_cansleep(ts_nbus->ale, 1);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 190)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 191) ts_nbus_write_byte(ts_nbus, val);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 192) ts_nbus_start_transaction(ts_nbus);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 193) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 194)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 195) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 196) * read the value in the FPGA register at the given address.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 197) * return 0 on success or negative errno on failure.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 198) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 199) int ts_nbus_read(struct ts_nbus *ts_nbus, u8 adr, u16 *val)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 200) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 201) int ret, i;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 202) u8 byte;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 203)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 204) /* bus access must be atomic */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 205) mutex_lock(&ts_nbus->lock);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 206)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 207) /* set the bus in read mode */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 208) gpiod_set_value_cansleep(ts_nbus->txrx, 0);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 209)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 210) /* write address */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 211) ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 212)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 213) /* set the data gpios direction as input before reading */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 214) ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_IN);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 215)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 216) /* reading value MSB first */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 217) do {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 218) *val = 0;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 219) byte = 0;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 220) for (i = 1; i >= 0; i--) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 221) /* read a byte from the bus, leave on error */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 222) ret = ts_nbus_read_bus(ts_nbus, &byte);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 223) if (ret < 0)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 224) goto err;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 225)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 226) /* append the byte read to the final value */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 227) *val |= byte << (i * 8);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 228) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 229) gpiod_set_value_cansleep(ts_nbus->csn, 1);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 230) ret = gpiod_get_value_cansleep(ts_nbus->rdy);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 231) } while (ret);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 232)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 233) err:
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 234) /* restore the data gpios direction as output after reading */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 235) ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_OUT);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 236)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 237) mutex_unlock(&ts_nbus->lock);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 238)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 239) return ret;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 240) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 241) EXPORT_SYMBOL_GPL(ts_nbus_read);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 242)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 243) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 244) * write the desired value in the FPGA register at the given address.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 245) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 246) int ts_nbus_write(struct ts_nbus *ts_nbus, u8 adr, u16 val)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 247) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 248) int i;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 249)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 250) /* bus access must be atomic */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 251) mutex_lock(&ts_nbus->lock);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 252)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 253) /* set the bus in write mode */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 254) gpiod_set_value_cansleep(ts_nbus->txrx, 1);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 255)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 256) /* write address */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 257) ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 258)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 259) /* writing value MSB first */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 260) for (i = 1; i >= 0; i--)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 261) ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_VAL, (u8)(val >> (i * 8)));
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 262)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 263) /* wait for completion */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 264) gpiod_set_value_cansleep(ts_nbus->csn, 1);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 265) while (gpiod_get_value_cansleep(ts_nbus->rdy) != 0) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 266) gpiod_set_value_cansleep(ts_nbus->csn, 0);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 267) gpiod_set_value_cansleep(ts_nbus->csn, 1);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 268) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 269)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 270) mutex_unlock(&ts_nbus->lock);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 271)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 272) return 0;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 273) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 274) EXPORT_SYMBOL_GPL(ts_nbus_write);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 275)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 276) static int ts_nbus_probe(struct platform_device *pdev)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 277) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 278) struct pwm_device *pwm;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 279) struct pwm_args pargs;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 280) struct device *dev = &pdev->dev;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 281) struct ts_nbus *ts_nbus;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 282) int ret;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 283)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 284) ts_nbus = devm_kzalloc(dev, sizeof(*ts_nbus), GFP_KERNEL);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 285) if (!ts_nbus)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 286) return -ENOMEM;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 287)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 288) mutex_init(&ts_nbus->lock);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 289)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 290) ret = ts_nbus_init_pdata(pdev, ts_nbus);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 291) if (ret < 0)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 292) return ret;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 293)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 294) pwm = devm_pwm_get(dev, NULL);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 295) if (IS_ERR(pwm)) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 296) ret = PTR_ERR(pwm);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 297) if (ret != -EPROBE_DEFER)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 298) dev_err(dev, "unable to request PWM\n");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 299) return ret;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 300) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 301)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 302) pwm_get_args(pwm, &pargs);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 303) if (!pargs.period) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 304) dev_err(&pdev->dev, "invalid PWM period\n");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 305) return -EINVAL;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 306) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 307)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 308) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 309) * FIXME: pwm_apply_args() should be removed when switching to
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 310) * the atomic PWM API.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 311) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 312) pwm_apply_args(pwm);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 313) ret = pwm_config(pwm, pargs.period, pargs.period);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 314) if (ret < 0)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 315) return ret;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 316)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 317) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 318) * we can now start the FPGA and populate the peripherals.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 319) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 320) pwm_enable(pwm);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 321) ts_nbus->pwm = pwm;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 322)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 323) /*
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 324) * let the child nodes retrieve this instance of the ts-nbus.
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 325) */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 326) dev_set_drvdata(dev, ts_nbus);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 327)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 328) ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 329) if (ret < 0)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 330) return ret;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 331)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 332) dev_info(dev, "initialized\n");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 333)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 334) return 0;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 335) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 336)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 337) static int ts_nbus_remove(struct platform_device *pdev)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 338) {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 339) struct ts_nbus *ts_nbus = dev_get_drvdata(&pdev->dev);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 340)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 341) /* shutdown the FPGA */
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 342) mutex_lock(&ts_nbus->lock);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 343) pwm_disable(ts_nbus->pwm);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 344) mutex_unlock(&ts_nbus->lock);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 345)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 346) return 0;
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 347) }
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 348)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 349) static const struct of_device_id ts_nbus_of_match[] = {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 350) { .compatible = "technologic,ts-nbus", },
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 351) { },
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 352) };
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 353) MODULE_DEVICE_TABLE(of, ts_nbus_of_match);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 354)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 355) static struct platform_driver ts_nbus_driver = {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 356) .probe = ts_nbus_probe,
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 357) .remove = ts_nbus_remove,
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 358) .driver = {
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 359) .name = "ts_nbus",
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 360) .of_match_table = ts_nbus_of_match,
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 361) },
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 362) };
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 363)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 364) module_platform_driver(ts_nbus_driver);
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 365)
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 366) MODULE_ALIAS("platform:ts_nbus");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 367) MODULE_AUTHOR("Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 368) MODULE_DESCRIPTION("Technologic Systems NBUS");
5b143d2a6edea (Sebastien Bourdelin 2017-11-01 13:14:33 -0400 369) MODULE_LICENSE("GPL v2");
VisionFive2 Linux kernel
StarFive Tech Linux Kernel for VisionFive (JH7110) boards (mirror)
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