Use clock notifiers to avoid changing the clock rate to an out-of-range setting for already configured devices. This will allow dynamic configuration of the MSIOF parent clock.
Not-Signed-off-by: Geert Uytterhoeven <[email protected]> --- Not intended for upstream merge. --- drivers/spi/spi-sh-msiof.c | 65 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 63 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c index 72f80a088cddd395..656eaa4d03ed497b 100644 --- a/drivers/spi/spi-sh-msiof.c +++ b/drivers/spi/spi-sh-msiof.c @@ -53,6 +53,8 @@ struct sh_msiof_spi_priv { void *rx_dma_page; dma_addr_t tx_dma_addr; dma_addr_t rx_dma_addr; + struct notifier_block clk_rate_change_nb; + u32 dev_max_speed_hz; }; #define TMDR1 0x00 /* Transmit Mode Register 1 */ @@ -180,6 +182,10 @@ struct sh_msiof_spi_priv { #define IER_RFOVFE 0x00000008 /* Receive FIFO Overflow Enable */ +/* Maximum internal divider */ +#define MAX_DIV 1024 + + static u32 sh_msiof_read(struct sh_msiof_spi_priv *p, int reg_offs) { switch (reg_offs) { @@ -253,7 +259,7 @@ static struct { static void sh_msiof_spi_set_clk_regs(struct sh_msiof_spi_priv *p, unsigned long parent_rate, u32 spi_hz) { - unsigned long div = 1024; + unsigned long div = MAX_DIV; u32 brps, scr; size_t k; @@ -526,6 +532,53 @@ static void sh_msiof_spi_read_fifo_s32u(struct sh_msiof_spi_priv *p, put_unaligned(swab32(sh_msiof_read(p, RFDR) >> fs), &buf_32[k]); } +static int sh_msiof_clk_notifier_cb(struct notifier_block *nb, + unsigned long event, void *data) +{ + struct clk_notifier_data *ndata = data; + struct sh_msiof_spi_priv *p = + container_of(nb, struct sh_msiof_spi_priv, clk_rate_change_nb); + + // FIXME locking + + if (!p->dev_max_speed_hz) + return NOTIFY_OK; + + switch (event) { + case PRE_RATE_CHANGE: + dev_info(&p->pdev->dev, "%s: %pC old_rate %lu new_rate %lu\n", + "PRE_RATE_CHANGE", ndata->clk, ndata->old_rate, + ndata->new_rate); + if (p->dev_max_speed_hz < ndata->new_rate / MAX_DIV) { + dev_err(&p->pdev->dev, + "New parent clock rate too high for %u\n", + p->dev_max_speed_hz); + return NOTIFY_STOP; + } + if (p->dev_max_speed_hz > ndata->new_rate) { + dev_warn(&p->pdev->dev, + "New parent clock rate too low for %u, ignoring\n", + p->dev_max_speed_hz); + } + return NOTIFY_OK; + + case POST_RATE_CHANGE: + dev_info(&p->pdev->dev, "%s: %pC old_rate %lu new_rate %lu\n", + "POST_RATE_CHANGE", ndata->clk, ndata->old_rate, + ndata->new_rate); + return NOTIFY_OK; + + case ABORT_RATE_CHANGE: + return NOTIFY_OK; + + default: + dev_info(&p->pdev->dev, + "0x%lx: %pC old_rate %lu new_rate %lu\n", event, + ndata->clk, ndata->old_rate, ndata->new_rate); + return NOTIFY_DONE; + } +} + static int sh_msiof_spi_setup(struct spi_device *spi) { struct device_node *np = spi->master->dev.of_node; @@ -535,12 +588,14 @@ static int sh_msiof_spi_setup(struct spi_device *spi) rate = clk_get_rate(p->clk); max_speed_hz = rate; - min_speed_hz = rate / 1024; + min_speed_hz = rate / MAX_DIV; dev_info(&p->pdev->dev, "%s: master speed min %u max %u, device speed max = %u\n", __func__, min_speed_hz, max_speed_hz, spi->max_speed_hz); + p->dev_max_speed_hz = spi->max_speed_hz; + pm_runtime_get_sync(&p->pdev->dev); if (!np) { @@ -1263,6 +1318,10 @@ static int sh_msiof_spi_probe(struct platform_device *pdev) p->pdev = pdev; pm_runtime_enable(&pdev->dev); + p->clk_rate_change_nb.notifier_call = sh_msiof_clk_notifier_cb; + if (clk_notifier_register(p->clk, &p->clk_rate_change_nb)) + dev_warn(&pdev->dev, "Unable to register clock notifier.\n"); + /* Platform data may override FIFO sizes */ p->tx_fifo_size = chipdata->tx_fifo_size; p->rx_fifo_size = chipdata->rx_fifo_size; @@ -1299,6 +1358,7 @@ static int sh_msiof_spi_probe(struct platform_device *pdev) return 0; err2: + clk_notifier_unregister(p->clk, &p->clk_rate_change_nb); sh_msiof_release_dma(p); pm_runtime_disable(&pdev->dev); err1: @@ -1310,6 +1370,7 @@ static int sh_msiof_spi_remove(struct platform_device *pdev) { struct sh_msiof_spi_priv *p = platform_get_drvdata(pdev); + clk_notifier_unregister(p->clk, &p->clk_rate_change_nb); sh_msiof_release_dma(p); pm_runtime_disable(&pdev->dev); return 0; -- 1.9.1
