From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de> To: Samuel Ortiz <samuel.ortiz@intel.com> Cc: kernel@pengutronix.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, "Ying-Chun Liu (PaulLiu)" <paulliu@debian.org>, "Philippe Rétornaz" <philippe.retornaz@epfl.ch>, "Marc Reilly" <marc@cpdesign.com.au>, "Mark Brown" <broonie@opensource.wolfsonmicro.com>, "Samuel Ortiz" <sameo@linux.intel.com> Subject: [PATCH 2/7] MFD: mc13xxx workaround SPI hardware bug on i.Mx Date: Thu, 12 Jul 2012 11:57:48 +0200 [thread overview] Message-ID: <1342087073-3892-3-git-send-email-u.kleine-koenig@pengutronix.de> (raw) In-Reply-To: <1342087073-3892-1-git-send-email-u.kleine-koenig@pengutronix.de> From: Philippe Rétornaz <philippe.retornaz@epfl.ch> The MC13xxx PMIC is mainly used on i.Mx SoC. On thoses SoC the SPI hardware will deassert CS line as soon as the SPI FIFO is empty. The MC13xxx hardware is very sensitive to CS line change as it corrupts the transfert if CS is deasserted in the middle of a register read or write. It is not possible to use the CS line as a GPIO on some SoC, so we need to workaround this by implementing a single SPI transfer to access the PMIC. Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Marc Reilly <marc@cpdesign.com.au> Signed-off-by: Philippe Rétornaz <philippe.retornaz@epfl.ch> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com> Origin: next-20120712, commit:e4ecf6ea84d68aea5a9785e89f52672e1e126998 Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> --- drivers/mfd/mc13xxx-spi.c | 65 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 64 insertions(+), 1 deletion(-) diff --git a/drivers/mfd/mc13xxx-spi.c b/drivers/mfd/mc13xxx-spi.c index 5d1969f..03df422 100644 --- a/drivers/mfd/mc13xxx-spi.c +++ b/drivers/mfd/mc13xxx-spi.c @@ -54,6 +54,67 @@ static struct regmap_config mc13xxx_regmap_spi_config = { .max_register = MC13XXX_NUMREGS, .cache_type = REGCACHE_NONE, + .use_single_rw = 1, +}; + +static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size, + void *val, size_t val_size) +{ + unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0}; + unsigned char r[4]; + unsigned char *p = val; + struct device *dev = context; + struct spi_device *spi = to_spi_device(dev); + struct spi_transfer t = { + .tx_buf = w, + .rx_buf = r, + .len = 4, + }; + + struct spi_message m; + int ret; + + if (val_size != 3 || reg_size != 1) + return -ENOTSUPP; + + spi_message_init(&m); + spi_message_add_tail(&t, &m); + ret = spi_sync(spi, &m); + + memcpy(p, &r[1], 3); + + return ret; +} + +static int mc13xxx_spi_write(void *context, const void *data, size_t count) +{ + struct device *dev = context; + struct spi_device *spi = to_spi_device(dev); + + if (count != 4) + return -ENOTSUPP; + + return spi_write(spi, data, count); +} + +/* + * We cannot use regmap-spi generic bus implementation here. + * The MC13783 chip will get corrupted if CS signal is deasserted + * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller + * has the following errata (DSPhl22960): + * "The CSPI negates SS when the FIFO becomes empty with + * SSCTL= 0. Software cannot guarantee that the FIFO will not + * drain because of higher priority interrupts and the + * non-realtime characteristics of the operating system. As a + * result, the SS will negate before all of the data has been + * transferred to/from the peripheral." + * We workaround this by accessing the SPI controller with a + * single transfert. + */ + +static struct regmap_bus regmap_mc13xxx_bus = { + .write = mc13xxx_spi_write, + .read = mc13xxx_spi_read, }; static int mc13xxx_spi_probe(struct spi_device *spi) @@ -78,7 +139,9 @@ static int mc13xxx_spi_probe(struct spi_device *spi) mc13xxx->dev = &spi->dev; mutex_init(&mc13xxx->lock); - mc13xxx->regmap = regmap_init_spi(spi, &mc13xxx_regmap_spi_config); + mc13xxx->regmap = regmap_init(&spi->dev, ®map_mc13xxx_bus, &spi->dev, + &mc13xxx_regmap_spi_config); + if (IS_ERR(mc13xxx->regmap)) { ret = PTR_ERR(mc13xxx->regmap); dev_err(mc13xxx->dev, "Failed to initialize register map: %d\n", -- 1.7.10.4
WARNING: multiple messages have this Message-ID (diff)
From: u.kleine-koenig@pengutronix.de (Uwe Kleine-König) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/7] MFD: mc13xxx workaround SPI hardware bug on i.Mx Date: Thu, 12 Jul 2012 11:57:48 +0200 [thread overview] Message-ID: <1342087073-3892-3-git-send-email-u.kleine-koenig@pengutronix.de> (raw) In-Reply-To: <1342087073-3892-1-git-send-email-u.kleine-koenig@pengutronix.de> From: Philippe R?tornaz <philippe.retornaz@epfl.ch> The MC13xxx PMIC is mainly used on i.Mx SoC. On thoses SoC the SPI hardware will deassert CS line as soon as the SPI FIFO is empty. The MC13xxx hardware is very sensitive to CS line change as it corrupts the transfert if CS is deasserted in the middle of a register read or write. It is not possible to use the CS line as a GPIO on some SoC, so we need to workaround this by implementing a single SPI transfer to access the PMIC. Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Marc Reilly <marc@cpdesign.com.au> Signed-off-by: Philippe R?tornaz <philippe.retornaz@epfl.ch> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com> Origin: next-20120712, commit:e4ecf6ea84d68aea5a9785e89f52672e1e126998 Signed-off-by: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de> --- drivers/mfd/mc13xxx-spi.c | 65 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 64 insertions(+), 1 deletion(-) diff --git a/drivers/mfd/mc13xxx-spi.c b/drivers/mfd/mc13xxx-spi.c index 5d1969f..03df422 100644 --- a/drivers/mfd/mc13xxx-spi.c +++ b/drivers/mfd/mc13xxx-spi.c @@ -54,6 +54,67 @@ static struct regmap_config mc13xxx_regmap_spi_config = { .max_register = MC13XXX_NUMREGS, .cache_type = REGCACHE_NONE, + .use_single_rw = 1, +}; + +static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size, + void *val, size_t val_size) +{ + unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0}; + unsigned char r[4]; + unsigned char *p = val; + struct device *dev = context; + struct spi_device *spi = to_spi_device(dev); + struct spi_transfer t = { + .tx_buf = w, + .rx_buf = r, + .len = 4, + }; + + struct spi_message m; + int ret; + + if (val_size != 3 || reg_size != 1) + return -ENOTSUPP; + + spi_message_init(&m); + spi_message_add_tail(&t, &m); + ret = spi_sync(spi, &m); + + memcpy(p, &r[1], 3); + + return ret; +} + +static int mc13xxx_spi_write(void *context, const void *data, size_t count) +{ + struct device *dev = context; + struct spi_device *spi = to_spi_device(dev); + + if (count != 4) + return -ENOTSUPP; + + return spi_write(spi, data, count); +} + +/* + * We cannot use regmap-spi generic bus implementation here. + * The MC13783 chip will get corrupted if CS signal is deasserted + * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller + * has the following errata (DSPhl22960): + * "The CSPI negates SS when the FIFO becomes empty with + * SSCTL= 0. Software cannot guarantee that the FIFO will not + * drain because of higher priority interrupts and the + * non-realtime characteristics of the operating system. As a + * result, the SS will negate before all of the data has been + * transferred to/from the peripheral." + * We workaround this by accessing the SPI controller with a + * single transfert. + */ + +static struct regmap_bus regmap_mc13xxx_bus = { + .write = mc13xxx_spi_write, + .read = mc13xxx_spi_read, }; static int mc13xxx_spi_probe(struct spi_device *spi) @@ -78,7 +139,9 @@ static int mc13xxx_spi_probe(struct spi_device *spi) mc13xxx->dev = &spi->dev; mutex_init(&mc13xxx->lock); - mc13xxx->regmap = regmap_init_spi(spi, &mc13xxx_regmap_spi_config); + mc13xxx->regmap = regmap_init(&spi->dev, ®map_mc13xxx_bus, &spi->dev, + &mc13xxx_regmap_spi_config); + if (IS_ERR(mc13xxx->regmap)) { ret = PTR_ERR(mc13xxx->regmap); dev_err(mc13xxx->dev, "Failed to initialize register map: %d\n", -- 1.7.10.4
next prev parent reply other threads:[~2012-07-12 10:13 UTC|newest] Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-07-12 9:57 [PATCH 0/7] Add support for Freescale's mc34708 to mc13xxx driver Uwe Kleine-König 2012-07-12 9:57 ` Uwe Kleine-König 2012-07-12 9:57 ` [PATCH 1/7] MFD: Fix mc13xxx SPI regmap Uwe Kleine-König 2012-07-12 9:57 ` Uwe Kleine-König 2012-07-12 9:57 ` Uwe Kleine-König [this message] 2012-07-12 9:57 ` [PATCH 2/7] MFD: mc13xxx workaround SPI hardware bug on i.Mx Uwe Kleine-König 2012-07-12 9:57 ` [PATCH 3/7] rtc/mc13xxx: use MODULE_DEVICE_TABLE instead of MODULE_ALIAS Uwe Kleine-König 2012-07-12 9:57 ` Uwe Kleine-König 2012-07-12 9:57 ` [PATCH 4/7] rtc/mc13xxx: add support for the rtc in the mc34708 pmic Uwe Kleine-König 2012-07-12 9:57 ` Uwe Kleine-König 2012-07-12 9:57 ` [PATCH 5/7] mfd/mc13xxx: drop modifying driver's id_table in probe Uwe Kleine-König 2012-07-12 9:57 ` Uwe Kleine-König 2012-07-12 9:57 ` [PATCH 6/7] mfd/mc13xxx: change probing details for mc13xxx devices Uwe Kleine-König 2012-07-12 9:57 ` Uwe Kleine-König 2012-07-13 15:22 ` Uwe Kleine-König 2012-07-13 15:22 ` Uwe Kleine-König 2012-07-12 9:57 ` [PATCH 7/7] mfd/mc13xxx: add support for mc34708 Uwe Kleine-König 2012-07-12 9:57 ` Uwe Kleine-König 2012-07-12 23:02 ` [PATCH 0/7] Add support for Freescale's mc34708 to mc13xxx driver Marc Reilly 2012-07-12 23:02 ` Marc Reilly 2012-07-13 8:48 ` Uwe Kleine-König 2012-07-13 8:48 ` Uwe Kleine-König 2012-07-13 19:39 ` Junio C Hamano 2012-09-05 14:22 ` Fabio Estevam 2012-09-05 14:22 ` Fabio Estevam 2012-10-04 13:01 ` Fabio Estevam 2012-10-04 13:01 ` Fabio Estevam 2012-10-04 13:51 ` Samuel Ortiz 2012-10-04 13:51 ` Samuel Ortiz 2012-10-04 14:11 ` Uwe Kleine-König 2012-10-04 14:11 ` Uwe Kleine-König 2012-10-27 19:19 ` Fabio Estevam 2012-10-27 19:19 ` Fabio Estevam 2012-11-06 22:24 ` Samuel Ortiz 2012-11-06 22:24 ` Samuel Ortiz 2012-08-02 15:52 ` Fabio Estevam 2012-08-02 15:52 ` Fabio Estevam
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